The present invention generally relates to a medical device for implantation in a living body, and more particularly relates to a clip lock mechanism for lead wires used with an implantable medical device.
A variety of devices exist which make use of electrical lead wires, i.e., leads or lead extensions, that detachably connect to an electrical device. For instance, numerous medical devices, such as neural stimulation devices, cardiac pacemakers and defibrillators, commonly establish a connection between an implanted lead or lead extension (herein, both will be referred to as xe2x80x98leadxe2x80x99) and an implanted electronic package. In a typical pacemaker, the proximal end of a lead is connected to an implantable pulse generator, while the distal end, containing one or more electrodes, is typically inserted in or on the heart.
It is preferable that the leads be detachable from the devices so that either may be implanted, explanted or replaced without affecting the other. Detaching and attaching the lead to the device should be simple, to reduce surgical time, and evident, to limit chances for error. In addition, it is preferable that attachment and detachment be possible without a tool. While the lead is attached to the device, the connection should be strong enough to resist flexing and any other forces that could unintentionally disconnect the lead.
The connection between a lead and an implantable device is preferably compact and light-weight, and it must be constructed of biocompatible materials and in such a way so that the electronic circuitry can survive for extended periods of time without any significant changes in performance. In addition to the connection being mechanically reliable, so that a lead does not inadvertently become disconnected from the device, it must also ensure proper electrical communication between the device and lead(s) at all times.
It is known in the art to use a set screw for each connection, often providing electrical contact, as well as mechanical connection, between the lead(s) and the device. This arrangement requires delicate and time-consuming surgical procedures ensuring that the set screw is secure yet does not strip, and that the device is not damaged. In addition, this arrangement is rather bulky. Also, sealing set screws from the surrounding body fluids is often difficult, as the seal may be damaged during tightening of the set screw.
There exists a need in the art for a compact, easy to operate, fast, and reliable way to detachably secure leads to implantable electronic packages.
The present invention addresses the above and other needs by providing a clip lock mechanism for securing lead wires, i.e., lead or lead extension, to an, implantable neurostimulator, or similar implantable device.
The clip lock mechanism of the present invention preferably applies to an enclosure made of a case and a header. However, the invention also may be used with one-piece devices, i.e. headerless enclosures, as well as with multi-piece enclosures. With the case and header enclosure, the case is made of a biocompatible material (e.g. titanium or ceramic) and houses an electronic circuit assembly (hereafter also referred to as xe2x80x9celectronic circuitryxe2x80x9d, xe2x80x9ccircuitryxe2x80x9d, or xe2x80x9celectronicsxe2x80x9d).
The header, which is typically made of polymeric material, such as epoxy, is secured (e.g. molded in place) to the case. The header has a plurality of electrical connectors (electrical feed-through terminals) passing through it connecting to the electronic components inside the case. In addition, the header has a receptacle(s) where a lead connector(s) at the proximal end of a lead(s) or lead extension(s) is inserted to form the electro-mechanical connection between the electronics and leads.
The clip lock mechanism provided by the present invention is typically made of a medical grade metal such as 316 stainless steel or nitinol. The clip lock mechanism pivotally connects to the header. The lead connector (at the proximal end of a lead or lead extension) comprises at least one pin and a plug. Once the pin(s) of the connector have been inserted into the receptacle, the clip is pivoted over the lead plug. The plug preferably has depressions that provide a clear visual and tactual indication of the position of the properly placed clip. Advantageously, manipulation of the clip is straight-forward, simple, and tool-less, yet the clip is reliably locked in place and requires intentional manipulation to be unlatched.